Playing doom3 for the third time, about 4 hours last night with 5.1 phones on. Beat it on Marine and Veteran levels, now I am on nightmare. Strange, rooms that I was able to get into seems to not be available now, maybe because I blew up the zombie when he was trying to throw a barrel at me, which then caused me to loose a step into the room. Found some other neat stuff in game which I missed the first two times through. Now I am in Alpha labs. One thing about Nightmare is there are no health packs around, the health units on the wall are there but once you go above 25% you deplete rather quickly to 25% health automatically, bummer. At least you have the Soul Cube to keep your health up .